Problem Description
When using custom pixmaps with QCPScatterStyle::ssPixmap on high DPI displays, the rendered scatter points appear blurry or are positioned incorrectly.
Environment
QCustomPlot Version: [2.1.1]
Qt Version: [6.9.1]
Platform: Windows 11 with high DPI display (100%+ scaling)
Display: High DPI monitor with devicePixelRatio > 1.0
Root Cause Analysis
The issue occurs in QCPScatterStyle::drawShape() for the ssPixmap case (around line 10999).
fix suggestions:

case ssPixmap:
    {
      const qreal dpr = mPixmap.devicePixelRatio();
      const double widthHalf = mPixmap.width()/dpr*0.5;
      const double heightHalf = mPixmap.height()/dpr*0.5;
#if QT_VERSION < QT_VERSION_CHECK(4, 8, 0)
        const QRectF clipRect = painter->clipRegion().boundingRect().adjusted(-logicalWidthHalf, -logicalHeightHalf, logicalWidthHalf, logicalHeightHalf);
#else
      const QRectF clipRect = painter->clipBoundingRect().adjusted(-widthHalf, -heightHalf, widthHalf, heightHalf);
#endif
      if (clipRect.contains(x, y))
        painter->drawPixmap(qRound(x-widthHalf), qRound(y-heightHalf), mPixmap);
      break;
    }